Ethylene and propene by oxidative dehydrogenation of ethane and propane - 'Performance of rare-earth oxide-based catalysts and development of redox-type catalytic materials by combinatorial methods'

Selected aspects related to the mode of reactor operation and to the develo pment of catalysts for the oxidative dehydrogenation of ethane and propane to their respective olefins are dealt with. The differences in the catalyti c conversion when applying ethane or propane on rare-earth-oxide (REO)-base d catalysts leading to the ignition of the reaction mixture are discussed. For ethane dehydrogenation, ethylene yields up to 46% were achieved by non- isothermal operation. Non-isothermicity was caused by ignition of the react ion and the resultant heat production. The formation of ethylene occurred v ia thermal pyrolysis and oxidative dehydrogenation. In general, autothermal operation looks promising for the production of ethylene from ethane. The advantage of REO-based catalysts as compared to noble metals like Pt is the ir high thermal stability. There are, however, limitations regarding the de hydrogenation of propane to propene in the autothermal mode. A high propene yield is not possible when applying such conditions since C-C scission res ults in a decrease of propene selectivity. The search for new active and se lective formulations operating at low temperatures is, therefore, still tim ely. Against this requirement, special attention was given to a combinatori al and evolutionary approach for the selection and optimization of catalyti c materials for the oxidative dehydrogenation of propane; selected experime ntal results as a proof of principle are presented. (C) 2000 Elsevier Scien ce B.V. All rights reserved.